A possessive 'determiner' (for example 'my', 'your', or 'his') refers to the gender of what is being 'possessed', indicates whether it is singular or plural, and also links back to who is possessing it.

For example: my bed - Mon lit

In this case the word 'Mon' indicates that the object possessed is masculine, that it is singular, and that is mine. So once you're determined who is the possessor you must determine the number and gender of the object possessed. The table below shows all the possessives :